Electrical resistance



J. COLLINSON.

ELECTRICAL RESISTANCE.

APPLIVCATION FILED SEPT- 9. IQIG.

Patented Feb. 24,1920. v

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JOHi J (JQLLIHSQTLT, 0F MANCHESTER, ENGLAND ASSIGNOR T6 WESTINGHOUSE ELECTRIC A1333 IVIANUFACTURING COMPANY, A CORPORATION OI IENNSYLVANIA.

ELECTRICAL REsis'rAiIcE.

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Specification of Letters Patent. Fgrtgntqgoi 2 4, 1920.

Application filed September 9, 1916. Serial No. 119,319.

of the rid t ue. and it has for its ob ect to provide an improved construction of grid for use in resistance devices of this type.

It-has heretofore been proposed to provide an electrical resistance device of the grid type con tructed from a strip of sheet metal in which a number of transverse cuts or slits are made by passing the sheet through a punching press or rolls,-such as are used for the production of expanded metal, the sheet being used as an electrical resistance in the condition in which it comes from the punching press or rolls, that is, without being expanded.

According to my present invention, a grid resistance is formed from a strip of sheet metal which is transversely corrugated and in which a number of cuts or slits, extending parallel to the corrugations, are made by any suitable means. By reason of the transverse corrugations, the grid is consid- 'erably strengthened and made more compact in the longitudinal direction relatively to an uncorrugated grid or" the same currentcarrying capacity constructed from sheet metal.

The invention is illustrated in the accompanying drawing, in which Figure 1 is an edgewise view of a corrugated strip of sheet metal from which an electrical grid resistance is constructed according to the present invention; Fig. 2 is a plan view of the grid resistance shown in Fig. 1, illustrating a. suitable arrangement of transverse cuts or slits in the said strip; Fig. 3 is an enlarged sectional view taken on the line IIIIII of Fig. 2, illustrating a preferred construction; Fig. 4 is a plan view of two half corrugations constructed in the manner illustrated in Fig. 3.

Referring to the drawings, a strip of sheet metal 1. consisting of any desired metal having the required electrical conductivity; is provided with transverse corrugations '2. by means of anysuita ole corragating device, and along the crests of the corrugations, cuts or slits 3 are provided in order to increasethe resistance otthe strip. The operations of corrugatin the metal strip 1 and of forming therein the cuts or slits 2 may be performed separately by successive operations; or they may be carried out sin'iultaneouslyby one and the same operation, by passing the sheet 1 through suitable corrugating and punching rolls.

In the preferred form of the invention shown in Fig. 3, one side 4' of each cut or slit 3 is bent away from the opposite side,

this arrangement being adapted to prevent the opposite sides of the cuts from coming into contact and so causing short circuits.

Uncut or uncorrugated portions 5 are left at each end of a grid so as to enable the latter to be easily secured in position in a resistance frame or box.

I claim as my invention:

1. An electric-resistance element comprising a slotted and corrugated sheet of conducting materiahzsemral of the slots being unconnected and disposed in alinement.

An electric-resistanceelement comprising a sheet of conducting material provided with a plurality of alined, unconnected slots having edges laterally displaced with reference to the body of the sheet.

8. An electric-resistance element comprising a sheet of conducting material provided with a plurality of corrugations and with slots extending along the crests of said corrugations.

4. An electric resistance element comprising asheet of conducting material provided with parallel corrugations and with a plurality of slots extending substantially along the crests of said corrugations one of each of the adjacent edges being depressed.

5. An electric-resistance element comprising a sheet of conducting material provided with parallel corrugations and with slots disposed in staggered relation and extending substantially parallel to the said corrugations and to each other.

6. An electricresistance element comprising a sheet of conducting material provided with parallel corrugations and with slots extending along the crests of the said corrugations.

7. An electric-resistance element comprising a sheet of conducting material provided Inn) with 510% disposed in staggered r clzilion and extending substantially parallel to the said corrugations and in each ether, the said slots having their :uljmaent edge. bent 011%; of contact Willi each other.

9 An cleellie-resistance element comprising a corrugated sheet elf conducting 1nateriul having; a plurality of nn connected slots extending zilcng the crests (if the corrugzn tiens.

10. An eleviiric-i'esis'hince element c0niprising a corrugated sheel of cend'uciving Ina,- liei'ial having a plurality of unconnected slots extending along the crests of the cori'ugziiicns, one edge of each cf said slots ce ing depressed.

11. An elcc'ln'ic-resistzince clement coniprising :1 sheet of; conducting i'hzi'berial luv-- ing the general contour of 1- preiileierinined surface and provided with slots, one edge of each cfsevei'zil 0E said slots lying in said surface and the other edge lying outside of said surface.

12. An electric-resistance element comprising a sheet of conducting material provided with slots, certain. of said slots having their adjacent edges bent in one direction onl-v of contact with each other and certain other 01? said slots having their edges bent in zinollicr direction out of contact Win11 each other.

13. An electric-resistance element comprising a ccrrngat-cd sheet of conducting ineterial having stz ggered slots.

ll. An electric-resistance element C0111- prising a sheet of cenducting material having slots, the opposite edges of certain of said. slots being laferally displaced to different degrees with respect to said sheet.

An electric-resistance element comprising a sheet of conducting material having a plurality of laterally displaced portions each provided with an openin f.

In testimony whereof, I have hereunto subscribed my name this tenth day of Aw gust, 1916.

JUHIN CULLINSON. Witnesses F. B. How, JAs. STEWART BROADFOOT. 

